Comparison of Coxiella burnetii Shedding in Milk of Dairy Bovine, Caprine, and Ovine Herds

Abstract

The shedding of Coxiella burnetii in bovine, caprine, and ovine milk was measured using PCR, in 3 herds for each species, the bulk tank milk samples of which were positive at the time of their selection. Milk samples of 95 cows, 120 goats, and 90 ewes were sampled over 16 wk, as was the bulk tank milk. The shedding of C. burnetii in vaginal mucus and feces was checked at the beginning of the experiment and 2 mo later. The clinical signs in the selected herds as well as the duration and the shedding routes differed among the 3 species. The cows were asymptomatic and shed C. burnetii almost exclusively in milk. In one of the caprine herds, abortions due to C. burnetii were reported. The goats excreted the bacteria mainly in milk. In contrast, the ewes, which came from flocks with abortions due to Q fever (C. burnetii infection), shed the bacteria mostly in feces and in vaginal mucus. This could explain why human outbreaks of Q fever are more often related to ovine flocks than to bovine herds. These excretions did not seem more frequent when the samples were taken close to parturition. The samples were taken from 0 to 421 d after parturition in bovine herds and from 5 to 119 d and 11 to 238 d after parturition in the caprine and ovine herds, respectively. The shedding in milk was sometimes intermittent, and several animals shed the bacteria but were negative by ELISA: 80% of the ewes were seronegative, underscoring the lack of sensitivity of the ELISA tests available for veterinary diagnosis. The detection of antibodies in milk seems more sensitive than it is in serum.

Coxiella burnetii in bulk tank milk and antibodies in farm workers at Montería, Colombia

“…PCR detection of C . burnetii in bovine milk has not been totally standardized because bacterium excretion patterns by cattle can be intermittent or continuous (Rodolakis, 2007). We cannot conclude that the farms with negative results were totally free of C .…”

“…Domestic ruminants such as cattle, goats and sheep are known to be the principal source of human infection (Maurin and Raoult, 1999). Bacterial shedding occurs in mammals trough placenta, birth fluids, vaginal mucus, feces, and milk (Berri et al, 2001;Arricau-Bouvery et al ., 2003;Guatteo et al ., 2007a;Rodolakis et al ., 2007). C .…”

“…Metritis and infertility are clinical signs of infection in cattle; however the infection is frequently subclinical (Rodolakis, 2009) despite the occurrence of C . burnetii shedding (Rodolakis et al ., 2007).…”

Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

“…On livestock farms, C. burnetii DNA has been found in various environmental matrices, such as dust (11-13) and aerosols (14-16). However, studies that examine the relationship between environmental contamination levels and the clinical status and shedding dynamics of ruminant herds are lacking.Although it is known that C. burnetii may be shed by infected domestic ruminants via birth products, vaginal secretions, feces, and milk (1,(17)(18)(19)(20)(21)(22), studies looking at the duration of individual shedding and the relative importance of the different shedding routes have yielded inconsistent results (3, 17-19, 21, 23). However, longitudinal follow-up studies performed on cattle (18, 24) and goat (21, 25-27) farms have been particularly valuable in providing descriptive data on individual shedding patterns and revealing the factors that may affect shedding dynamics.…”

Determination of Coxiella burnetii in bovine foetuses using PCR and immunohistochemistry

“…In the placenta, it has been found in trophoblasts and mononuclear cells (Bildfell et al 2000). C. burnetii is reported to be transmitted by environmental contamination with placental secretions, vaginal mucus, faeces, milk, and similar products from infected animals (Berri et al 2000;Rodolakis et al 2007).…”